This was the 3rd place winner of the 2004 ray tracing competition POVCOMP 2004. I used to play around with POV-Ray a bit back when I was in high school, but I'll be damned if I ever did anything that compares to these. Here were some of the other winners:

That's the idea. One of the proposed uses for nanobots is that you could program them to repair someone's cells or fix medical problems, and then inject them into the bloodstream and let them do their work. Definitely sci-fi for the time being, but not entirely out of the realm of possibility.